It is generally known to provide a plural bin system for mixing multiple ingredients, such as fertilizer and fertilizer supplements, and spreading or broadcasting the mixture over a ground surface. For example, U.S. Pat. No. 3,073,606 to Hurt discloses an apparatus including a multiplicity of bins which are separated from each other for carrying material ingredients with transversely oriented metering screw auger conveyors disposed underneath the bins such that equal amounts of ingredients are discharged from the bins. The discharge of each of the ingredients from the transverse screw auger conveyors is equally divided by four longitudinally extending screw auger conveyors that discharge the ingredients onto a transverse screw auger conveyor at the rear of the apparatus. The mechanical complexity of this system has many moving parts requiring substantial maintenance and operating costs. In addition, this system does not have the ability to easily vary the spread rates of the different materials.
U.S. Pat. No. 6,817,551 to Williams, et al. discloses a convertible plural bin and conveyor material spreader. In this device, the material bin may be converted from a single bin to a plural bin apparatus and vice versa by the insertion or removal of a self-contained bin having its own separable conveyor. Thus, each bin has its own conveyor for discharging material ingredients from the bin, with the conveyors disposed one over the other.
In spite of the existence of these devices, there remains a need for equipment that is capable of spreading a plurality of different materials/ingredients at independently varying rates that is more economical than existing devices. There also exists a need for spinner spreader equipment that is capable of spreading a plurality of different material ingredients with some at ultra low rates.